1. Field of the Invention
This invention relates to an optical card apparatus wherein, in case a track number fails to be read, re-seeking will be made by moving an optical head in a tracking direction relatively to an optical card.
2. Description of the Related Art
Such card-like information recording medium as is shown in FIG. 1 has been already suggested. In this optical card 151, information is reproduced by detecting the reflection factor variation of the recording surface and is recorded by physically varying the recording surface. Such information is recorded or reproduced by a unit called a track and a plurality of linear band-like tracks 152 are parallelly arranged to form one optical card 151.
In the optical card 151 shown in FIG. 1, so that a target track may be sought, each track 152 is provided at both ends respectively with ID regions 153a and 153b in which its track number is recorded and between these ID regions with a data region 154 for recording data and also a card driving pattern 155 for controlling the card drive.
In such optical card 151 in which the track numbers of the ID regions 153a and 153b are recorded in the tracking direction, that is, the data leading direction, generally the track pulses are counted while the reading head is being moved in the track width direction, that is, the seeking direction, the movement of the reading head is stopped at a predetermined counted value, then the optical card 151 is moved in the leading direction and the track number is read so that the target track may be sought.
However, as described above, in reading the track number by moving the optical card 151 in the leading direction, there is a problem that, when the read track number is not of the target track due to a track pulse counting mistake or the like, unless after the data region 154 of the track is scanned, re-seeking will not be able to be made and therefore the access to the target track will take time.
In order to solve such problem, for example, in the publication of Japanese Patent Application Laid Open No.240481/1986, there is disclosed a system wherein a plurality of the track numbers of respective tracks are recorded at predetermined intervals in the tracks so that, when a mis-seek is produced, the target track may be sought by reading the track number of another track by moving the reading head in the seeking direction while moving the optical card 151 in the reading direction.
However, in order to seek the target track by moving the reading head in the seeking direction while moving the optical card 151 in the leading direction as mentioned above, there are problems that the formation and control will be complicated. That, in case the difference between the mis-sought track and the target track is large, the target track will not be able to be sought during the movement in the leading direction and that, when a plurality of the track numbers of respective tracks are recorded at predetermined intervals in the tracks, the data region will become so narrow that the recording capacity of the medium is effectively reduced.